This invention is in the field of rotational position and velocity sensing for a rotatable shaft and more particularly to an internal combustion engine crankshaft or camshaft position and velocity sensing and output device for driving the coils for spark ignition devices in the engine cylinders of such engine.
In previous systems for controlling the ignition coil drivers for spark ignition devices in an internal combustion engine, mechanical devices such as the well known distributor system having a camshaft driven distributor arm and arcuately spaced contacts were used to energize an ignition coil and high voltage pulses to the spark ignition devices, commonly known as spark plugs, in each cylinder. A cam on the distributor arm shaft operated a pair of contacts, or "points", to deliver a low voltage pulse to the ignition coil for each high voltage pulse to the spark plugs. This system required frequent maintenance, adjustment, and part replacement.
Other systems have been devised, some utilizing Hall-effect sensors and rotors with magnetic sensing devices, to provide a distributorless ignition system but have not found general use due to inherent system expense and operation limitations.